1720128913 has 2 divisors, whose sum is σ = 1720128914. Its totient is φ = 1720128912.

The previous prime is 1720128887. The next prime is 1720128929. The reversal of 1720128913 is 3198210271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1423703824 + 296425089 = 37732^2 + 17217^2 .

It is an emirp because it is prime and its reverse (3198210271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1720128913 is a prime.

It is not a weakly prime, because it can be changed into another prime (1720128953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 860064456 + 860064457.

It is an arithmetic number, because the mean of its divisors is an integer number (860064457).

Almost surely, 2^1720128913 is an apocalyptic number.

It is an amenable number.

1720128913 is a deficient number, since it is larger than the sum of its proper divisors (1).

1720128913 is an equidigital number, since it uses as much as digits as its factorization.

1720128913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 1720128913 is about 41474.4368617586. The cubic root of 1720128913 is about 1198.1752156620.

The spelling of 1720128913 in words is "one billion, seven hundred twenty million, one hundred twenty-eight thousand, nine hundred thirteen".